Hi

I purchased the C4000 in October of last year and it has performed well up until recently.  I am now getting periodic connection drops.  I am not a network guy so not sure if it is the router, modem or ISP.  I did look at my modem log and I do see a number of entries as follows:

No Ranging Response received - T3 time-out

Ranging Request Retries exhausted

Unicast Maintenance Ranging attempted - No response - Retries exhausted

Cable Modem Reboot due to T4 timeout

I did do a Google search and I am thinking it may be an ISP issue and not router related, but would appreciate any guidance from folks more knowledgeable than me.  I don't want to start replacing hardware, modem or router, if not required.  Thanks in advance for any help.